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Composition-Dependent Phase Evolution of Reactive-Sintered AlON
Shuixian Yang1,2, Xiaojian Mao3, Run Tian3, Jian Zhang3, Shiwei Wang3
1 National Demonstration Center For Experimental Physics Education, Nanjing University, Nanjing 210093, China.
2 School of Physics, Nanjing University, Nanjing 210093, China
3 State Key Laboratory of High Performance Ceramics, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201899, China
received December 3, 2025, received in revised form January 6, 2026, accepted January 17, 2026
Pages 1-10 DOI: 10.4416/JCST2025-00038
Abstract
Based on an investigation of the reactive sintering behavior of Al2O3-AlN up to 1 950 °C, a comprehensive framework is established for understanding the multi-stage reactive sintering process of AlON ceramics. The process comprises four distinct stages: (1) initial densification dominated by Al2O3 sintering, during which preferential Al2O3 grain growth delays AlON formation; (2) formation of a nitrogen-rich AlON solid solution, accompanied by lattice and volumetric expansion; (3) dissolution of residual Al2O3 into the AlON lattice, together with lattice contraction and volumetric shrinkage; (4) final densification of phase-pure AlON. This mechanism is consistently verified across a broad composition range of 22 – 40 mol% AlN, offering critical insights for process optimization. Furthermore, blackening of the sintered sample is identified as an inevitable intermediate stage during the densification of AlON ceramics, which is unrelated to phase impurities or carbon contamination.
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Keywords
Aluminum oxynitride (AlON), reactive sintering behavior, blackening
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